To further characterize the nature of Beta2-microglobulin (beta2m)-associated polypeptide chains on the surface of normal and neoplastic human lymphocyte populations with emphasis toward characterization of any non-HLA beta2m-associated products. To evaluate the possible relationships of beta2m with various soluble factors and mediators in extracellular fluids, primarily serum and urine, especially in specimens from leukemic patients. To isolate and characterize beta2m in mice and rats and to prepare antisera to these beta2m which will then be used in studies designed to delineate further the relationship between beta2m and the various products of the major histocompatibility complex and the biological role of beta2m in immune responsiveness. To undertake an investigation from a phylogenetic approach of the structure of the major histocompatibility antigens in lower vertebrates, primarily the avian species.